Tribology Day symposium to address large diameter heads and new implant designs

A major Tribology Day session at the 13th EFORT 2012 Congress will review indications for large diameter heads and cover the optimal implants for patients.

  • Orthopaedics Today Europe [Archives], Issue 2

A session scheduled for this year’s Tribology Day at the 13th EFORT Congress 2012 in Berlin will focus on the role large diameter heads play in hip arthroplasty, advantages of conforming vs. non-conforming bearings and indications for metal-on-metal large heads, according to meeting organizers.

Paolo Tranqulli Leali, MD, of the University of Sassari in Italy, and Christina Doyle, PhD, of Exeter, England, co-organized the 1.5-hour session scheduled to take place Friday, May 25 at 9:15 in the Istanbul auditorium. Tranquilli Leali told Orthopaedics Today Europe the symposium will be dedicated to the problems of articulation and will make the case for using large diameter heads, but will also address new technology, such as ultra-highly crosslinked polyethylene and ceramic articulations. 

Paolo Tranqulli Leali
Paolo Tranqulli Leali

“The main take-home message is large is good. A larger head gives the patient a more physiological range of motion and very good proprioception,” Tranqulli Leali said. “From the point of view of the surgeon, there is an almost impossible dislocation of the joint because the larger the head, the lower the risk of dislocation.”

Controversy of metal articulations

Tranquilli Leali noted that a large diameter head with a low dislocation rate is most favorable for elderly patients, where a reoperation can sometimes be fatal. Additionally, he said he will present on the clinical aspects of large metal-on-metal heads during the symposium, a topic which has drawn controversy because of the material’s adverse effects in some patients due to wear or incorrect implant placement.

“It is known from the Australian register [that] the main problem in metal-metal joints is the ‘human factor,’ so an incorrect positioning of the implant can increase the wear at very dangerous levels,” Tranquilli Leali said.

Update on polyethylene, ceramic

Among others scheduled to participate in the session is John Fisher, PhD, director of the University of Leeds Institute for Medical and Biological Engineering, in the United Kingdom, where a ceramic-on-metal hip implant was developed. He is scheduled to discuss non-conforming bearings.

Other planned symposium participants include Robert Streicher, PhD, of Zurich, who is expected speak about conforming bearings, and Eduardo Garcia-Rey, MD, PhD, of Madrid. Garcia-Rey is scheduled to present information on the clinical aspects of new polyethylene material, according to the preliminary program.

“In this presentation, he will present some future propositions for new kinds and new categories of implants and preliminary work on new materials and new components in arthroplasty surgery in [the] hip and knee,” Tranquilli Leali said. – by Jeff Craven

Reference:
  • Tranquilli Leali P, Doyle C. Large diameter heads: Risk/benefit? Scheduled to be presented May 25, 9:15-10:45, at the 13th EFORT Congress 2012. May 23-25. Berlin.
For more information:
  • Prof. Paolo Tranquilli Leali, MD, can be reached at the Department of Orthopaedics, University of Sassari, 21 University Square, 07100 Sassari, Italy; +39 079 228 036; email: tranquilli@uniss.it.
  • Disclosure: Tranquilli Leali has no relevant financial disclosures.

Perspective

  • Crosslinked polyethylene (PE) has become accepted as the worldwide standard articulating material for acetabular components in total hip arthroplasty. With long-term use in more active patients, wear debris and osteolysis resulting in loosening and revision arthroplasty led to the introduction of other articulating materials like ceramic-on-ceramic and metal-on-metal. With hard-on-hard articulation materials needing further technological improvement, toughened alumina ceramics were developed with a low risk of fracture that seems to have overcome the poor reputation of earlier ceramic materials.

    Meanwhile, standard ultra-high molecular weight PE benefitted from being highly crosslinked. But, to produce better highly crosslinked PE, clinical experiences and mechanical tests demonstrated the need for further improvement. This led to highly crosslinked PE being enhanced with vitamin E. Early data on this material seems to confirm the value of this improvement.

    During the last 10 years, there was a “match” between results with highly crosslinked PE, ceramic and metal bearings mainly because of using large diameter heads. Although recent experiences seem to reduce the chance of metal-on-metal articulations from winning this “competition,” 28-mm and 32-mm diameter metal-on-metal heads have achieved excellent outcomes. Currently, ceramic-on-ceramic is increasingly used internationally. However, the worldwide leader, crosslinked PE, has still been further improved to achieve the goal of all articulating materials: lifelong function for every patient, especially younger active patients, without producing wear and osteolysis.

    • Karl Knahr, MD
    • Orthopaedics Today Europe
      Editorial Board member
      Vorstand der Abteilung Orthopädie II
      Orthopädisches Spital Speising GmbH
      Vienna
  • Disclosures: Knahr has no relevant financial disclosures.

Comments

Healio is intended for health care provider use and all comments will be posted at the discretion of the editors. We reserve the right not to post any comments with unsolicited information about medical devices or other products. At no time will Healio be used for medical advice to patients.